Over the years, many kinds of prostheses have been devised in effort to replace the limbs that amputees have lost. In particular, many efforts have been made to develop prostheses that will replace the loss of major limbs such as legs and arms in view of the immense impact that such a loss has on the amputee. All these prostheses have the difficult task of giving to these amputees a life as normal as possible. The task is particularly difficult for leg prostheses due in part to the complexity of human locomotion. Conventional leg prostheses have until now only been using passive mechanisms in the most sophisticated available devices. Conventional leg prostheses are very limited compared to a real human leg and some needs were thus not entirely fulfilled by them.
According to amputees, specific conditions of use of conventional leg prostheses, such as repetitive movements and continuous loading, typically entail problems such as increases in metabolic energy expenditures, increases of socket pressure, limitations of locomotion speeds, discrepancies in the locomotion movements, disruptions of postural balance, disruptions of the pelvis-spinal column alignment, and increases in the use of postural clinical rehabilitation programs.
Another problem is that during the amputees' locomotion, energy used for moving the prosthesis mainly originates from the amputees themselves because conventional leg prostheses do not have self-propulsion capabilities. This has considerable short and long-term negative side effects. Recent developments in the field of energy-saving prosthetic components have partially contributed to improve energy transfer between the amputees and their prosthesis. Nevertheless, the problem of energy expenditure is still not fully resolved and remains a major concern.
A further problem is that the dynamic role played by the stump during the amputees' locomotion renders difficult the prolonged wearing of conventional leg prostheses. This may create, among other things, skin problems such as folliculitis, contact dermatitis, oedema, cysts, skin shearing, scarring and ulcers. Although these skin problems may be partially alleviated by using a silicone sheath, a complete suction socket or powder, minimizing these skin problems remain a concern.
Similar considerations apply in other prostheses, to a greater or lesser extent as dictated by the particular conditions that are imposed on the prosthesis.
It is therefore an object of the present invention to obviate or mitigate the above disadvantages.